U.S. Pat. No. 3,905,888 discloses one particular oxygen sensor for use in vivo in the vasculature of a human or animal. The disclosure of the '888 patent is hereby incorporated by reference and made a part of the background of this disclosure. The anode is typically longer and made of silver. The cathode is shorter and made of a noble metal, such as gold, platinum or silver. The anode and cathode are immersed in an electrolyte, an appropriate potential is applied therebetween and a current flow between them is monitored as an indication of oxygen content in the electrolyte. If holes exist in the insulation of the cathode, dendrites will grow through the hole to the anode and short out the sensor. To avoid that problem another approach has been tried. Specifically, the length over which an uninsulated portion is next to an insulated part is minimized. That geometric arrangement is prone to earlier failure because the metal consumed tends to be at the base of the anode near the distal end of the insulation. Specifically, that is the site for the short path for flow of current between the anode and the cathode. After a short while the tip of the anode becomes separated from its insulated base once the silver thereat has been consumed.
The need to provide a longer lived and more reliable design for the conductors in an electrochemical cell is not fulfilled by the '888 patent.